KR20100045939A - Drilling tool - Google Patents

Abstract

PURPOSE: A drilling tool is provided to enhance the breakage prevention characteristic during drilling and improve the roughness of a drilled surface. CONSTITUTION: A drilling tool comprises one or more spiral chip discharging grooves(2) and a clearance forming tip(4). The spiral chip discharging grooves are formed on the outer surface of a tool body(1) from the leading end to the base end. The clearance forming tip is formed between the chip discharging groove and a land(3), lower than the land.

Description

Drilling tool {DRILLING TOOL}

The present invention relates to a drilling tool.

In the drill 25 which has the blade part 20 in which the cutting edge which drills a workpiece is formed in the front end side, and has the shank part hold | maintained by a tool holder in the base end side, for example, it is a patent As disclosed in Document 1, a clearance forming end 23 one step lower than the land portion 22 is formed between the chip discharge groove 21 and the land portion 22, and the so-called clearance ( There are two blade drills with clearance 24.

This clearance 24 is generally provided in predetermined length from the drill tip as shown in FIG. Therefore, compared with the drill 25 'without clearance as shown in FIG. 2, the volume of the chip discharging groove (the space for chip discharging) is increased and the chip discharging performance is excellent, while the outer circumference at the tip of the drill is excellent. There is a problem that the progress of wear is faster and the life is shortened by that amount.

In addition, in the case where the clearance 24 is provided up to the drill tip, the tip shape becomes complicated as much as the part forming the clearance 24, and the processing becomes cumbersome (particularly cumbersome when the diameter decreases).

In addition, when performing the external appearance inspection of the tip shape of the drill at the time of the tip, when the width | variety of the land part 22 after the clearance 24 is formed, or when there are multiple, they measure their mutual difference, and also clearance In the case of the depth of 24 or a plurality of them, their mutual difference is measured to determine whether they are good or bad. However, when the diameter is smaller, not only the processing but also this inspection is cumbersome, and the high cost cannot be avoided.

[Patent Document 1] Japanese Patent Laid-Open No. 2005-131751

The present invention has been made in view of the above-described phenomena, and it is possible to suppress wear at the outer circumference of the tip to improve the fracture resistance at the time of drilling, and to improve the inner wall roughness and regrindability. It is to provide a highly practical drilling tool having a simple structure and easy manufacturing.

The gist of the present invention will be described with reference to the accompanying drawings.

One or more spiral chip discharge grooves 2 are formed in the outer periphery of the tool body 1 from the tool tip toward the base end side, and the chip discharge groove 2 and the land portion 3 are formed between the chip discharge grooves 2 and the land portion 3. A drilling tool provided with a clearance forming end portion 4 one step lower than the land portion 3, wherein the clearance forming end portion 4 is provided only at the tool base end side without being provided at the tool tip side. It is about a tool.

In the drilling tool of claim 1, the clearance forming end portion 4 is provided toward the tool base end side from a position separated by a distance of 1.5 to 5 times the tool outer diameter D1 from the tool tip. A drilling tool characterized by the above-mentioned.

Further, in the drilling tool according to claim 2, the clearance forming end portion 4 relates to a drilling tool, characterized in that provided in a range not exceeding the end position of the chip discharge groove (2).

Further, in the drilling tool described in claim 3, the clearance forming end portion 4 relates to a drilling tool, which is provided at a depth of 5 to 20% of the tool outer diameter D1.

Moreover, in the drilling tool of Claim 4, the said clearance formation edge part 4 is related with the drilling tool characterized by being provided in the same depth from the start end to the end.

Furthermore, in the drilling tool of Claim 5, the said clearance formation end part 4 relates to the drilling tool characterized by being provided in the tool rotation direction front side of the said chip | tip discharge groove 2.

Further, in the drilling tool according to any one of claims 1 to 6, the seam thickness D2 of the tool body 1 is a front in which the seam thickness D2 gradually increases from the tool tip toward the base end direction. A perforation tool, characterized in that it is set to a front tapered shape.

Furthermore, in the drilling tool of Claim 7, the front taper shape of the said core thickness D2 is set so that the inclination angle of the tool tip side may become large and the inclination angle of the tool base end side may become small. It is about.

Furthermore, the drilling tool of Claim 8 WHEREIN: It is related with the drilling tool characterized by the tool outer diameter D1 being 0.2 mm or less.

Since the present invention is constituted as described above, it is possible to suppress the wear of the outer circumference to improve the fracture resistance at the time of drilling, and to improve the inner wall roughness and regrinding, and the structure is simple and easy to manufacture. It becomes the drilling tool which is extremely practical.

EMBODIMENT OF THE INVENTION Embodiment of this invention which thinks it is suitable is demonstrated based on drawing of the action of this invention based on drawing.

When the workpiece is drilled, the groove volume of the chip discharge groove 2 is enlarged by the clearance formed by the clearance forming end 4, so that the chip is discharged well and the clearance is improved at the tip. Since it does not exist, the land part 3 of the tool tip side which is easy to contact with a workpiece is hard to be worn, and wear of the outer periphery of a tool tip side is suppressed by that much. Therefore, since the chip becomes difficult to be clogged, the breakage resistance at the time of drilling is improved, and the loss to the inner wall of the processing hole by the chip can be reduced, and the inner wall roughness can be improved by that much.

Further, for example, even when the outer shape of the tool is set to a back taper shape in which the tool outer diameter is not constant and gradually decreases from the tool tip toward the base end direction, the wear on the outer circumference of the tool tip side is suppressed. The tapered shape is maintained and the breakage life can be increased.

In addition, it is possible to manufacture simply by forming a clearance from the tool intermediate part of the land part 3 to the base end side, and also the tool tip shape is not complicated, and manufacturing and external inspection can be performed simply and easily by that much. Become. In addition, since the outer circumference of the tool tip wears little, it can be fixed stably on the blade support, and also excellent in the regrinding property, for example, to easily secure the diameter after regrinding.

In addition, for example, when the core thickness D2 of the tool main body 1 is set to the front taper shape which the said core thickness D2 gradually increases toward a base end direction from a tool tip, it is set by a front taper shape. It is possible to remarkably increase the groove volume while securing sufficient seam thickness at the tool base end side, thereby suppressing chip clogging, and in particular, to provide excellent fracture resistance.

EXAMPLE

Specific embodiments of the present invention will be described with reference to FIGS. 3 to 11.

In this embodiment, one or more spiral chip discharge grooves 2 are formed on the outer periphery of the tool main body 1 from the tool tip toward the base end side, and the chip discharge groove 2 and the land portion 3 are formed. Is a drilling tool provided with a clearance forming end portion 4 lower than the land portion 3 between the land portion 3, and the clearance forming end portion 4 is provided only at the tool base end side without being installed at the tool tip side. It is.

Specifically, the present embodiment has a blade portion 6 having a tool outer diameter D1 (diameter) of about 0.1 mm, and having a cutting edge 5 formed on the tip side with a perforated workpiece. A drill for a printed wiring board (PCB) having a shank portion (7) held at a tool holder on the base end side, and two chip discharge grooves (2) are provided on the outer circumference of the blade portion (6), and this chip discharge groove ( The land part 3 is provided between 2), and the cutting blade 5 is provided between the chip | tip discharge groove 2 and the drill tip flank surface, respectively. The tip flank is also inclined with respect to the tool axis center at a predetermined angle to form a chisel edge in the center of the drill. In the figure, reference numeral 8 denotes a connecting portion between the blade portion 6 and the shank portion 7.

On the other hand, in the present embodiment, a PCB drill having a diameter of about 0.1 mm is used, but the present invention can be similarly applied to a case where the diameter is smaller or the diameter is larger. In particular, it is suitable to use for the small diameter drill of 0.2 mm or less (about 0.05 mm).

Each part is explained concretely.

The clearance forming end portion 4 faces the tool base end side from a position (starting end) separated by a distance of 1.5 to 5 times the tool outer diameter D1 from the tool tip, and the tool from the end position of the chip discharge groove 2. It is provided to the front end side (end). In the case of the installation from a distance less than 1.5 times the tool outer diameter D1, it is difficult to obtain a sufficient effect of suppressing the wear of the outer circumference of the tool tip, and the land portion 3 disappears during regrinding. If the end 4 is exposed and there is a risk that the end 4 is installed from a position more than five times the tool outer diameter D1, the clearance forming end 4 does not exist, so that a sufficient groove volume cannot be secured. It is because the defect that the fluidity | liquidity of a chip deteriorates and a chip becomes easy to be clogged arises.

In the present embodiment, the tool tip end side of the blade 6 is slightly smaller than the end position of the chip discharging groove 2 from the position separated by about twice the distance of the tool outer diameter D1 from the tool tip end. It is provided to a position (to the position of the vicinity of the connection part with the taper part 8 of the blade part 6 in the range of A in FIG. 4). Specifically, the end of the clearance forming end 4 is provided to a position away from the end of the chip discharging groove 2 toward the tool tip side by about 1 to 10% of the length of the groove of the chip discharging groove 2. . On the other hand, the end of the clearance forming end 4 may be provided so as to be at the same position as the end of the chip discharge groove 2, and the point is to secure a sufficient groove volume, and the end position of the chip discharge groove 2; It is good to install in the range which does not exceed.

Therefore, the clearance 9 does not exist in the front-end | tip part of a tool, but is provided over the base end side from the middle part of a tool.

In addition, the clearance forming end part 4 is 5-20% of the depth of the tool outer diameter D1, and it is the same depth from a start end to an end (step surface of the clearance formation end part 4 from a land part surface). So that the distance to (10) becomes constant. At less than 5% of the tool outer diameter D1, the clearance forming end 4 is too shallow, so that the increase in groove volume is small and chips are easily clogged, and when it exceeds 20%, the rigidity of the drill decreases. This is because not only the performance such as hole position accuracy and the like deteriorate, but also the defect that the fracture resistance deteriorates due to the lack of rigidity of the drill occurs. In this embodiment, it is provided in the depth of about 10% of the tool outer diameter D1.

Moreover, the connection surface 11 which connects the step surface 10 of the land part surface and the clearance formation end part 4 in succession is the step surface 10 of the clearance formation end part 4 in the axial cross section of a drill. The angle α to be formed is set to be an obtuse angle (about 120 ° in this embodiment). This is because if α is an acute angle, the chip is likely to be filled in the corner portion where the stepped surface 10 and the connecting surface 11 intersect, which causes deterioration of chip discharging property in the entire drill and easy breakage. .

In addition, the clearance formation end part 4 is provided in the tool rotation direction front side of the chip | tip discharge groove 2. Specifically, in this embodiment, the land portion of the drill without clearance as shown in FIG. 2 is removed from the middle portion of the tool, and the land portion 3 is used as the land portion 3 in the tool rotation direction front side. The step surface 10 is formed in the end part of the said connection surface 11 through the said. On the other hand, the cutting blade 5 is provided on the rear side of the tool rotation direction of the chip discharge groove 2 as the tool tip.

In addition, the shim thickness D2 of the tool main body 1 is set to the front taper shape in which the said shim thickness D2 gradually increases toward a base end direction from a tool tip. Specifically, as shown in FIG. 4, the front taper shape of the seam thickness D2 is set so that the inclination angle is large in the area F1 on the tool tip side and the inclination angle is small in the area F2 on the tool base end side. . Thus, as apparent from Fig. 5 showing the cross section of the drill of this embodiment and Fig. 6 showing the cross section of the drill 25 'without clearance shown in Fig. 2, the volume of the chip discharge space can be significantly increased. It is possible to suppress chip clogging by the clearance 9 while ensuring sufficient seam thickness D2 at the tool base end by the front taper shape, and it is especially excellent in fracture resistance.

In addition, in this embodiment, although the tool outer diameter D1 (outer diameter of the blade part 6 of the tool main body 1) is made into the back taper shape gradually decreasing toward the base end direction from a tool tip, For example, the outer shape of the tool may be configured such that the tool outer diameter is substantially constant from the leading end to the base end.

Since the present embodiment is configured as described above, when the workpiece is drilled, the groove volume of the chip discharge groove 2 is enlarged due to the clearance formed by the clearance forming end 4, and the chip Not only is this discharged satisfactorily, but there is no clearance at the distal end, so that the land portion 3 on the side of the tool tip which is easily in contact with the workpiece is less likely to be worn, and wear of the outer circumference at the distal end of the tool is suppressed. Therefore, it is easy to maintain stable drilling, and thus the breakage resistance at the time of drilling is improved, and the breakage resistance is improved even when the chip becomes difficult to be clogged, and the loss to the inner wall of the processing hole by the chip can be reduced. The inner wall roughness can be improved by that amount.

In addition, even when the outer shape of the tool is set to a back taper shape in which the tool outer diameter is not constant and gradually decreases from the tool tip toward the foundation end direction, the back taper shape is maintained by suppressing the wear of the outer circumference of the tool tip side. Thus, it becomes possible to increase the break life.

In addition, it is possible to manufacture simply by forming a clearance from the tool middle part of the land part 3 to the base end side, and also to make it simple and easy to carry out manufacture and an external inspection as much as the tool tip shape is not complicated. It becomes possible. In addition, since the outer circumference of the tool tip wears little, it can be fixed stably on the blade support, and also excellent in the regrinding property, for example, to easily secure the diameter after regrinding.

Moreover, even if the shim thickness D2 of the tool main body 1 is set to the front taper shape which the said shim thickness D2 gradually increases toward a base end direction from a tool tip, the front taper shape is sufficient by the tool base end side. It is possible to remarkably increase the groove volume while securing the core thickness to suppress chip clogging, and in particular, to provide excellent fracture resistance.

Therefore, this embodiment can suppress the wear of the outer circumference of the tip to improve the fracture resistance at the time of drilling, and also to improve the inner wall roughness and regrinding property, and furthermore, the practicality is simple in structure and easy to manufacture. Excellent drilling tool.

The experimental example which demonstrates the effect of this Example is demonstrated.

On the other hand, the normal clearance in the table and graph refers to the general clearance formed from the tool tip as shown in Fig. 1, the sub-clearance according to the present embodiment as shown in Fig. The clearance formed from the middle part of the tool not to be formed at the tip of the tool.

FIG. 7 shows the outer circumferential wear state after 18000 hits of PCB for each of 3 samples for each of FIGS. 1 (normal clearance), 2 (no clearance), and 3 (sub clearance: this example). It is a graph showing the result of a measurement. In addition, a new article shows the state before a punching process. In addition, the measurement was performed at 0.01 mm pitch in 0.2 mm range from a drill tip. Each sample measured the same conditions, such as a raw material, length, and a diameter except the formation range of presence or absence of clearance.

As is apparent from FIG. 7, the outer clearance was suppressed to the same extent as the type without the clearance, and it was confirmed that the outer clearance was superior to the normal clearance type compared to the clearance type.

8 and 9 show the results of damage evaluation by 12000 PCB hits in each sample.

As is clear from Figs. 8 and 9, the sub clearance type has a much longer life span than the type without the clearance, and the breakage life is increased by suppressing the outer circumference wear on the normal clearance as well. It was found to be extremely excellent.

10 and 11 show four samples of overlapping PCBs with 6000 hits, and then measured ten points of roughness of the inner wall of the processing holes of the PCB. The results are shown for each overlapping position of the PCB. The PCB of the uppermost part (tool inrush side) is described as the top, and the PCB of the lowermost part (tool protruding side) is described as bottom.

10 and 11, it was confirmed that the inner clearance of the sub clearance type is significantly improved compared to the type without clearance, and moreover, the inner wall roughness similar to the normal clearance can be maintained even without clearance at the tip of the tool.

As mentioned above, according to the present Example, it was confirmed that it can suppress the outer periphery of a front-end | tip part, and it can improve the fracture resistance at the time of a drilling process, and can improve the inner wall roughness and regrinding property.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic explanatory side view of the drill which provided the conventional clearance.

2 is a schematic explanatory side view of a conventional clearance free drill.

3 is a schematic explanatory side view of the present embodiment.

4 is a schematic explanatory diagram of the present embodiment.

FIG. 5 is an enlarged schematic cross-sectional view illustrating an enlarged portion of FIG. 3. FIG.

FIG. 6 is an enlarged schematic cross-sectional view illustrating an enlarged portion of FIG. 2. FIG.

Fig. 7 is a graph showing experimental results regarding outer circumference wear.

8 is a table showing experimental results regarding breakage.

9 is a graph showing experimental results regarding breakage.

10 is a table showing experimental results relating to inner wall roughness.

11 is a graph showing experimental results regarding inner wall roughness.

<Description of the symbols for the main parts of the drawings>

1: tool body

2: chip discharge groove

3: land part

4 end for forming clearance

D1: Tool Outside Diameter

D2: seam thickness

Claims (9)

One or more spiral chip discharge grooves are formed in the outer periphery of the tool body from the tool tip toward the base end side, and a clearance forming end one step lower than the land portion is formed between the chip discharge groove and the land part. A drilling tool provided, wherein the clearance forming end portion is provided not only on the tool tip side, but only on the tool base end side. The drilling tool according to claim 1, wherein the clearance forming end portion is provided toward the tool base end side from a position separated by a distance of 1.5 to 5 times the tool outer diameter from the tool tip end. The drilling tool according to claim 2, wherein the clearance forming end portion is provided within a range not exceeding the end position of the chip discharge groove. The drilling tool according to claim 3, wherein the clearance forming end is provided at a depth of 5 to 20% of the tool outer diameter. The drilling tool according to claim 4, wherein the clearance forming end is provided at the same depth from the start end to the end. The drilling tool according to claim 5, wherein the clearance forming end is provided on the front side of the tool discharging direction of the chip discharging groove. 7. The drilling tool according to any one of claims 1 to 6, wherein the shim thickness of the tool body is set to a front taper shape in which the shim thickness gradually increases from the tool tip toward the base end direction. The drilling tool according to claim 7, wherein the front taper shape of the seam thickness is set so that the inclination angle of the tool tip side is large and the inclination angle of the tool base end side is small. 9. The drilling tool of claim 8, wherein the tool outer diameter is 0.2 mm or less.

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